A conventional solar cell structure with a p-type base has a negative electrode that is typically on the front-side or sun side of the cell and a positive electrode on the backside. It is well-known that radiation of an appropriate wavelength falling on a p-n junction of a semiconductor body serves as a source of external energy to generate hole-electron pairs in that body. Because of the potential difference which exists at a p-n junction, holes and electrons move across the junction in opposite directions and thereby give rise to flow of an electric current that is capable of delivering power to an external circuit. Most solar cells are in the form of a silicon wafer that has been metallized, i.e., provided with metal contacts that are electrically conductive.
U.S. Pat. No. 7,435,361 to Carroll at al. is directed to a thick film conductive composition useful in a solar cell. The composition has a zinc-containing additive being ZnO, and the composition provides a Pb-free system which maintains electrical performance and solder adhesion.
Although various methods and compositions for forming solar cells exist, there is a need for zinc containing compositions which have improved electrical performance. The present invention fulfills such need.